1. Field of the Invention
This invention relates to a hand-operated pump that is readily accessible and useable by people with disabilities. This pump complies with the American Disabilities Act (ADA) and allows persons with disabilities access to potable water by applying a maximum force of 5 pounds (22.2 newtons) to the pumping mechanism. It would find application as an installment at camp sites, undeveloped vacation property, recreational fields, parks, farms, ranches and industrial settings. It would be especially useful in the National Forest System campgrounds and recreational areas.
2. Description of the Prior Art
Standard farm and campground hand pumps comprise a reciprocating positive displacement piston encased in a cylinder located in an underground water supply. The piston is driven by a pump rod that reciprocates vertically within a water supply line. The reciprocal motion of the pump rod is provided by a handle that the user xe2x80x9cpumpsxe2x80x9d in an up-and-down motion. Typically, pumps of this design require good strength and body leverage to operate effectively.
Various approaches have been taken in an effort to substitute a rotary motion for the more conventional up-and-down pumping motion of hand pumps. Foughty (U.S. Pat. No. 4,475,872) relates to a progressing cavity pump, wherein a screw-like helical rotor turns eccentrically within a helical stator. Input power is supplied by the user to a rotary, horizontal shaft and is then transferred to a vertical pump drive shaft by means of a gear box. A combination of gears and clutches allows the user to rotate the power input shaft in either direction without damage to the pump.
The Simple(trademark) Pump Company manufactures a motorized pump that transfers the rotary motion of an electric motor to a reciprocating up-and-down motion of the pump rod by means of a Scotch yoke. An adjustable pin arm driven by the motor permits selection of a predetermined pump stroke and various head pressures.
There are variations of the Scotch yoke such as the synchronized Scotch yoke taught by Clegg (U.S. Pat. No. 4,603,593). This device employs curved cam tracks resembling in shape a reclining figure eight. Each degree of revolution of the crank pin produces uniform displacement of the reciprocating member, and power is distributed evenly throughout the stroke.
Other mechanisms for converting rotary motion to reciprocal motion and vice versa are known in the art. For example, Brackett (U.S. Pat. No. 5,456,159) discloses a conjugate drive motion translator comprising a system of interacting members including a reciprocating linearly moving shuttle, a pair of opposing conjugate bearings, a pair of conjugate drivers rotatably mounted to the crankpin of crankshaft with the axis of crankshaft rotation perpendicular to the linear path of the shuttle.
In view of various complexities associated with the aforementioned devices, none fully meets the needs of many individuals with disabilities requiring access to well water in undeveloped areas.
We have now discovered a reliable hand-operated pump, readily accessible and useable by people with disabilities, for use in campgrounds and other remote areas where electricity is not available. The design of the pump obviates the undue force and lengthy stroke of conventional reciprocating handle-type hand pumps, and complies with the specifications set forth in the ADA.
In accordance with this discovery, it is an object of this invention to provide a hand pump that can be operated with one hand and requires the user to apply no more than 5 pounds (22.2 newtons) of force to the pumping mechanism within a vertical range of 12 inches (30 cm) between 28 and 40 inches (0.7-1 m) from the ground.
It is a further object of this invention to provide a hand pump that fully meets the specifications of the ADA.
It is also an object of the invention to provide a hand pump that is simple in design, inexpensive to produce, operates reliably in the field, and requires very little maintenance.
Another object of the invention is to convert user-applied rotary motion to a reciprocating pump rod.
Other objects and advantages of this invention will become readily apparent from the ensuing description.